The present invention relates to paper making processes and system for the processes. More particularly, the present invention relates to a paper making process and system using an enzyme and cationic coagulant combination to improve cellulosic pulp drainage and/or retention.
Conventional paper making processes generally include the following steps: (1) forming an aqueous suspension of cellulosic fibers, commonly known as pulp; (2) adding various processing and paper enhancing materials, such as strengthening, retention, drainage aid and/or sizing materials, or other functional additives; (3) sheeting and drying the fibers to form a desired cellulosic web; and (4) post-treating the web to provide various desired characteristics to the resulting paper, such as surface application of sizing materials, and the like. Some cellulase enzymes can be used to treat cellulosic fiber and improve the drainage of the fiber suspension slurry. However, enzyme usage has required an additional pretreatment process of heating the cellulosic pulp, such as preheating the pulp to approximately 50° C. for about 30-120 minutes before enzyme addition. Additional energy consumption and equipment installation is required for such preheating operations for enzyme usage. Further, enzymes can be costly, and enzyme application for papermaking would result in significant increases in production cost.
The present investigators have seen a need for additives useful in papermaking processing that can produce paper with improved cellulosic pulp drainage and retention in cost reduced manners.